What are these white/clear "crystals" forming on my shower door??

Question

I recently went on a long vacation and when I came back I noticed these sort of white/clear small mounds of crystal looking things had formed on the metal frame of my shower door. When I began cleaning it I noticed that the metal underneath had been eaten away!! Does anyone have any idea what I am looking at here?? Thank you.

Answer 1

Those white crystals are mineral deposits.  You probably have hard water.  Remove it with a cleaner that removes lime:  Lime away or CLR <Calcium, Lime, Rust>

After it is clean, wipe some Old English Lemon Oil on the metal frames.  It will prevent future build up.